docs: def set_string(self, string_options):
          """Set a series of properties using a string.
  
          For example::
  
              'fred=12, tile'
              '[fred=12]'
  
          """
  
          vo = ffi.cast('VipsObject *', self.pointer)
          cstr = _to_bytes(string_options)
          result = vips_lib.vips_object_set_from_string(vo, cstr)
  
          return result == 0